bad attitude and ignoring of CPA

Went to riverside mall and they didn't have the size I wanted but Emoyeni mall did, I drove there in order to get to the till with the pair and it scanned 1cent, the cashier shouted out that amount and quickly took a bar code for a size 28 to scan a size 38 pair of jeans, when questioned, she rapidly carried on with the transaction and said \you can't get the item for free"I asked to speak to the manager who then said \"" it's a problem from head office this is new stock and I only fixed one size"